syzbot


INFO: task hung in ext4_put_super

Status: upstream: reported C repro on 2021/05/25 03:18
Subsystems: ext4
[Documentation on labels]
Reported-by: syzbot+69a169605d24b16f9a9c@syzkaller.appspotmail.com
First crash: 1297d, last: 683d
Fix bisection: failed (error log, bisect log)
  
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.14 INFO: task hung in ext4_put_super ext4 C 4 656d 907d 0/1 upstream: reported C repro on 2022/06/19 21:08
upstream INFO: task hung in ext4_put_super ext4 C inconclusive done 1 1275d 1305d 20/28 fixed on 2021/11/10 00:50
Fix bisection attempts (5)
Created Duration User Patch Repo Result
2021/10/23 06:15 12m bisect fix linux-4.19.y error job log
2021/09/22 11:43 36m bisect fix linux-4.19.y OK (0) job log log
2021/08/23 10:38 29m bisect fix linux-4.19.y OK (0) job log log
2021/07/24 09:55 39m bisect fix linux-4.19.y OK (0) job log log
2021/06/24 09:17 30m bisect fix linux-4.19.y OK (0) job log log

Sample crash report:
EXT4-fs (loop0): re-mounted. Opts: (null)
EXT4-fs (loop0): re-mounted. Opts: (null)
EXT4-fs (loop0): re-mounted. Opts: (null)
EXT4-fs (loop0): re-mounted. Opts: (null)
INFO: task syz-executor271:8115 blocked for more than 140 seconds.
      Not tainted 4.19.211-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor271 D27744  8115   8113 0x00000000
Call Trace:
 context_switch kernel/sched/core.c:2828 [inline]
 __schedule+0x887/0x2040 kernel/sched/core.c:3517
 schedule+0x8d/0x1b0 kernel/sched/core.c:3561
 schedule_timeout+0x92d/0xfe0 kernel/time/timer.c:1794
 do_wait_for_common kernel/sched/completion.c:83 [inline]
 __wait_for_common kernel/sched/completion.c:104 [inline]
 wait_for_common+0x29c/0x470 kernel/sched/completion.c:115
 kthread_stop+0x109/0x6b0 kernel/kthread.c:588
 ext4_put_super+0x93c/0x1010 fs/ext4/super.c:1054
 generic_shutdown_super+0x144/0x370 fs/super.c:456
 kill_block_super+0x97/0xf0 fs/super.c:1185
 deactivate_locked_super+0x94/0x160 fs/super.c:329
 deactivate_super+0x174/0x1a0 fs/super.c:360
 cleanup_mnt+0x1a8/0x290 fs/namespace.c:1098
 task_work_run+0x148/0x1c0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:193 [inline]
 exit_to_usermode_loop+0x251/0x2a0 arch/x86/entry/common.c:167
 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
 do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fa445344ce7
Code: Bad RIP value.
RSP: 002b:00007ffe9fb844c8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fa445344ce7
RDX: 00007ffe9fb8458b RSI: 000000000000000a RDI: 00007ffe9fb84580
RBP: 00007ffe9fb84580 R08: 00000000ffffffff R09: 00007ffe9fb84360
R10: 0000555555727683 R11: 0000000000000202 R12: 00007ffe9fb855f0
R13: 00005555557275f0 R14: 00007ffe9fb844f0 R15: 00000000000003c7

Showing all locks held in the system:
1 lock held by khungtaskd/1570:
 #0: 00000000cc81273e (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441
1 lock held by syz-executor271/8115:
 #0: 00000000b1c87de9 (&type->s_umount_key#36){++++}, at: deactivate_super+0x16c/0x1a0 fs/super.c:359

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 1570 Comm: khungtaskd Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1a6/0x1f0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline]
 watchdog+0x991/0xe60 kernel/hung_task.c:287
 kthread+0x33f/0x460 kernel/kthread.c:259
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4681 Comm: systemd-journal Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
RIP: 0010:seccomp_run_filters+0x15f/0x590 kernel/seccomp.c:210
Code: 89 f7 e8 d4 cc ff ff 45 39 fe 7d 1e e8 da cb ff ff 48 8b 44 24 10 80 38 00 0f 85 8f 03 00 00 48 8b 44 24 08 41 89 ed 48 89 18 <e8> bc cb ff ff 48 8d 7b 08 48 89 f8 48 c1 e8 03 42 80 3c 20 00 0f
RSP: 0018:ffff8880a1b77bc0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff8880a1e84440 RCX: ffffffff8162b98c
RDX: 000000007fff0000 RSI: ffff8880a1b6a2c0 RDI: 0000000000000004
RBP: 000000007fff0000 R08: 0000000000000000 R09: 000000007fff0000
R10: 0000000000000004 R11: 0000000000000000 R12: dffffc0000000000
R13: 000000007fff0000 R14: 000000007fff0000 R15: 000000007fff0000
FS:  00007f2bde8db8c0(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2bdbd07028 CR3: 00000000a1bcf000 CR4: 00000000003406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __seccomp_filter+0x93/0xca0 kernel/seccomp.c:667
 __secure_computing+0xfc/0x360 kernel/seccomp.c:796
 syscall_trace_enter+0x563/0xd60 arch/x86/entry/common.c:121
 do_syscall_64+0x486/0x620 arch/x86/entry/common.c:283
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f2bddb73f17
Code: ff ff ff 48 8b 4d a0 0f b7 51 fe 48 8b 4d a8 66 89 54 08 fe e9 1a ff ff ff 66 2e 0f 1f 84 00 00 00 00 00 b8 27 00 00 00 0f 05 <c3> 0f 1f 84 00 00 00 00 00 b8 6e 00 00 00 0f 05 c3 0f 1f 84 00 00
RSP: 002b:00007ffe83fa7df8 EFLAGS: 00000202 ORIG_RAX: 0000000000000027
RAX: ffffffffffffffda RBX: 0000560053a5f1e0 RCX: 00007f2bddb73f17
RDX: 00000000ffffffff RSI: 00007ffe83fa7e80 RDI: 0000560053a5f1e0
RBP: 0000000000001249 R08: 00007ffe83fd2000 R09: 0000014bc7d96e16
R10: 001bc83cac9f0f07 R11: 0000000000000202 R12: 00007ffe83fa7e80
R13: 00007ffe83fa7e78 R14: 00005600533f0958 R15: 0005f3491c16313f

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/01/28 01:45 linux-4.19.y 3f8a27f9e27b 9dfcf09c .config console log report syz C [disk image] [vmlinux] [mounted in repro] ci2-linux-4-19 INFO: task hung in ext4_put_super
2023/01/02 21:03 linux-4.19.y 3f8a27f9e27b ab32d508 .config console log report syz C [disk image] [vmlinux] [mounted in repro] ci2-linux-4-19 INFO: task hung in ext4_put_super
2022/06/21 06:46 linux-4.19.y 3f8a27f9e27b 0fc5c330 .config console log report syz C ci2-linux-4-19 INFO: task hung in ext4_put_super
2021/05/25 03:17 linux-4.19.y 1e986fe9ad15 3c7fef33 .config console log report syz C ci2-linux-4-19 INFO: task hung in ext4_put_super
2023/01/29 06:24 linux-4.19.y 3f8a27f9e27b 9dfcf09c .config console log report info [disk image] [vmlinux] ci2-linux-4-19 INFO: task hung in ext4_put_super
* Struck through repros no longer work on HEAD.